Lubricating process with fibrous material in the hot extrusion of metals



March 3, 1953 ,J. SEJOURNET 2,630,220

LUBRICATING PROCESS WITH FIBROUS MATERIAL IN THE HOT EXTRUSION OF METALS Dem-19, 194

Fi l'ed 9 I 4 J INVEN TOR Jacques Sejournef HIS ATTORNEYS Patented Mar. 3, 1953 LUBRICATING PROCESS WITH FIBROUS' MATERIAL IN THE HOT EX'ERUSION Jacques Sejournet, Paris, France, assignor to Comptoir Industriel dEtirage et Profilage de Metaux, Paris, France, a corporation of France Application December 19, 1949, Serial No. 133,784 In France January 19, 1949 2 Claims.

In United States patent applications Nos. 597,266 of June 2, 1945, now abandoned, and 27,974 of May 19, 1948, now Patent No. 2,538,917, granted January 23, 1951, a method for the hot extrusion of diificultly extrudable metals was described. In that method, a lubricant material which is incombustible at the extrusion tempera ture and has a melting range at the extrusion temperature, as contrasted with a true melting point, is inserted between the ingot and the tool equipment of the press, more particularly between the ingot and the die, the heated ingot is introduced into the press and extruded in such manner that the portion of lubricant material in contact with the ingot continuously melts and fiows through the die along the extruded object while the remainder of the material remains in a solid state.

As disclosed in the above mentioned patent applications and in United States patent application No. 598,516 of June 9, 1945, it is often of advantage to give the die or the bottom of the container a generally concave shape. But it may easily be understood that certain difficulties may then arise when a fiat glass plate is applied against said curved surface.

Experience shows, more particularly, that the mechanical and thermal impact between the ingot and the glass plate results in breaking the plate into numerous pieces which no longer cover the ledge of the die in a uniform manner at the beginning of the extrusion process. Under these conditions certain parts of the die are no longer lubricated or are badly lubricated and it is found that the typical often described wear and tear appears.

The present invention which makes it possible to remedy these drawbacks is an improvement on the method which forms the subject-matter of the above mentioned patent applications. It essentially consists of a method for the hot extrusion of difiicultly extrudable metals by inserting between the ingot to be extruded and the tool equipment of the press a material which melts partially or totally under the action of the ingot heat while remaining viscous, in which method at least one portion of the said material is used in the form of a fibrous mass.

The invention is preferably carried into practice by using for the lubrication, one or more plates of a lubricating material which melts partially or totally under the action of the ingot heat while remaining viscous and one or more parcels or portions of fibres of the same or of another material substantially having this same, quality.

The invention yields results which are particularly good where one or more glass plates is or are used in combination with one or more parcels of glass fibre. Experience shows that under such conditions the thermal and mechanical impact is deadened and that under the influence of the pressure exerted by the ingot the parcel of glass fibres and the glass plate become deformed in a continuous manner and uniformly cover the various parts of the ledges of the die and of the die-holder before the beginning of the extrusion process.

All the drawbacks due to an irregular lubrication disappear and it is found that the most com plicated shapes of dies or die-holders may be conveniently lubricated by this means.

The word parcel is not to be limited here to a previously prepared element but includes merely a certain quantity of fibre taken from a loose mass and characterized mainly by its consistency and its weight. The parcel or parcels is or are placed in the container before the extrusion and are compressed by the ingot at the be-- ginning of the operation.

In accordance with the invention the parcel of glass fibre is placed preferably between the glass plate and the die. It is also possible to place this parcel between the ingot and the glass p ate.

The glass plate may also be placed between two glass fibre parcels. It is also possible to interpose, between the press and the ingot, one or more glass plates and one or more glass fibre parcels in any order.

Finally, it is possible to place only a glass fibre parcel of a sufficient volume between the die of the press and the ingot Without any interposition of a glass plate.

In the accompanying drawing two examples of execution of the invention are shown. In said drawing:

Figure 1 shows the placing in position of a glass fibre parcel between the die and the glass plate before the extrusion.

Figure 2 shows an extrusion process in which a glass plate was previously inserted between the ingot and the die between two glass fibre parcels.

In said figures, l designates the container, 2 the push-rod, 3 the ingot, t the glass fibre parcel or parcels, 5 the glass plate and 6 the hollow die. Finally, in Figure 2, l designates the extruded bar.

In all cases the volume of the glass fibre parcel must be chosen so that it is the larger, the smaller the total thickness of the glass plates.

Said volume must be the larger, the larger the hollow part of the die itself is.

The following examples illustrate this condition Example 1 On a 1500 tons press fifty bars of a fiat section of 45 mm. x 18 mm. were extruded from a mild steel ingot having a diameter of 145 mm. and a length of 700 mm. in a container having a diameter of 155 mm. The hollow die had a concavity the depth of which was 30 mm. For the lubrication a glass fibre parcel having a diameter of 150 mm. and a thickness of 50 mm. was used and placed between the die and a glass plate having a diameter of 150 mm. and a thickness of 3 mm. placed against the ingot.

Faultless bars were obtained and the tool equipment had undergone no appreciable wear and tear.

Example 2 On a 600 tons press sixty-five bars of a square section of 22 mm. x 22 mm. were extruded from a half-hard steel ingot having a diameter of 120 mm. and a length of 600 mm. in a container having a diameter of 128 mm. The hollow die showed a concavity the depth of which was 12 mm.

For the lubrication a glass plate having a diameter of 120 mm. and a thickness of 3.5 mm. was used and placed between two glass fibre parcels having a diameter of 120 mm. and a thickness of 15 mm.

Faultless bars were obtained and the tool equipment could still be used for the extrusion of other bars.

What I claim is:

1. In a method of extruding a metal workpiece from an extrusion chamber having a die at one end, the die having an opening through which the workpiece is extruded and a ledge surrounding the die opening, the steps comprising placing a layer of glass-like lubricating material which has a wide viscosity range at and is incombustible at the extrusion temperature and therefore has a melting range as contrasted with a true melting point, on the ledge around the die opening, the

layer being made up of fibers of the material, the 5 layer being of such dimension as to cover the 4 major portion of said ledge, said glass-like material being viscous at the pressure of extrusion beginning at a temperature below the extrusion temperature and ending at a temperature high enough to provide for layer melting during the entire extrusion operation, heating the workpiece and introducing it into the extrusion chamber, and extruding the workpiece at such rate that the fibers which are directly in contact with the workpiece melt continuously and under the pressure employed flow continuously through the die opening around the article being extruded, while the fibers in the opposite surface of said layer of lubricating material remains substantially solid. 2. In a method of extruding a metal workpiece from an extrusion chamber having a die at one end, the die having an opening through which the workpiece is extruded and a ledge surrounding the die opening, the steps comprising placing a layer of glass-like lubricating material which has a wide viscosity range at and is incombustible at the extrusion temperature and therefore has a melting range as contrasted with a true melting point, on the ledge around the die opening, the layer being composed entirely of glass-like material interspersed with voids, the layer being of such dimensions as to cover the major portion of said ledge, said glass-like material being viscous at the pressure of extrusion beginning at a temperature below the extrusion temperature and ending at a temperature high enough to provide for layer melting during the entire extrusion operation, heating the workpiece and introducing it into the extrusion chamber, and extruding the workpiece at such rate that the surface of said layer of lubricating material which is adjacent the workpiece melts continuously and under the pressure employed flows continuously through the die opening around the article being extruded while the opposite surface of said layer of lubricating material remains substantially solid.

JACQUES SEJOURNET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 567,410 Potter Sept. 8, 1896 2,538,917 Sejournet et al Jan. 23, 1951 

